From 1873bb8115e678ad9fd0aac9dbbc68383bc36e06 Mon Sep 17 00:00:00 2001 From: "Ahmed S. Darwish" <darwish.07@gmail.com> Date: Sat, 25 Dec 2010 11:57:09 +0200 Subject: [PATCH] RAMOOPS: Don't overflow over non-allocated regions The current code mis-calculates the ramoops header size, leading to an overflow over the next record at best, or over a non-allocated region at worst. Fix that calculation. Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com> Acked-by: Marco Stornelli <marco.stornelli@gmail.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --- drivers/char/ramoops.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/char/ramoops.c b/drivers/char/ramoops.c index 73dcb0ee41fda..d3d63be2cd37e 100644 --- a/drivers/char/ramoops.c +++ b/drivers/char/ramoops.c @@ -29,7 +29,6 @@ #include <linux/ramoops.h> #define RAMOOPS_KERNMSG_HDR "====" -#define RAMOOPS_HEADER_SIZE (5 + sizeof(struct timeval)) #define RECORD_SIZE 4096 @@ -65,8 +64,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, struct ramoops_context, dump); unsigned long s1_start, s2_start; unsigned long l1_cpy, l2_cpy; - int res; - char *buf; + int res, hdr_size; + char *buf, *buf_orig; struct timeval timestamp; /* Only dump oopses if dump_oops is set */ @@ -74,6 +73,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, return; buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE)); + buf_orig = buf; + memset(buf, '\0', RECORD_SIZE); res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR); buf += res; @@ -81,8 +82,9 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec); buf += res; - l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE)); - l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE) - l2_cpy); + hdr_size = buf - buf_orig; + l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - hdr_size)); + l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - hdr_size) - l2_cpy); s2_start = l2 - l2_cpy; s1_start = l1 - l1_cpy; -- GitLab